FLOW-INDUCED CORROSION KINETICS MODELOF DUPLEX STAINLESS STEEL IN FLOW LOOP SYSTEM

Wall function, k-e turbulence model are used in the present study.The numer ical hydrodynamics models and mass transfer models in flow loop system are defin ed in accordance with the basic theory of hydrodynamics and conservation of mass ,momentum and energy.Flow-induced corrosion kinetics model of duplex stainless steel in flowing 3.5% NaCl solution is set up on the basis of determining main controlling factors and their degree of influence in flow-induced corrosion by some electrochemical experiments,and of analyzing the kinetics process of f low-induced corrosion of duplex stainless steel. The numerical method used in this study is based on the control volume approach for discretization of partial differential equations that express the characteri stics of fluid flow and mass transfer.The user program is compiled.In accordance with flow-induced corrosion kinetics models,flow-induced corrosion rates are n umerically calculated with SIMPLE algorithm.The flow-induced corrosion rates cal culated by numerical method are compared with the ones measured by mass loss.The numerically computed flow-induced corrosion rates are mostly equal to th e ones measured by mass loss experiments.It proves that the flow-induced corrosion kine tics models are correct and accurate,and that the user program is reasonable.Th e models are founded on the basis of some electrochemical experim ents and reasonable hypothesis. Flow-induced corrosion of duplex stainless steel in flowing 3.5% NaCl solution is controlled by anodic pass ivation process and the diffusion or transfer process of ions in passivation fil m is a speed-controlling step.Corrosion electrochemical factor plays a dominant role in flow-induced corrosion of duplex stainless steel.